Combination lock



Feb; 23, 1960 Filed Oct. 5, 1951 H. c. MILLER 2,925,726

COMBINATION Locx 3 Sheets-Sheet l ATTORNEYS Feb. 23, 195o Filed Oct. 3. 195] H. C. MILLER COMBINATION LOCK s sheets-shea 2 pllmlll @1% @if M INVENTOR j ATTORNEYS Feb. 23, 19670 H. c. MILLER 2,925,726

COMBINATION Loox Filed Oct. 5, 1951 3 Sheets-Sheet 3 BY www ATTORNEYS United States Patent This invention relates to improvements in permutation locks, commonly referred to as combination locks.

This application covers improvements in the lock disclosed in my copending application S.N. 83,548, tiled March 26, 1949, now Patent No. 2,575,674, dated November 20, 1951.

Locks of the type commonly referred to as combina- ',tion locks are, of course, very well known. Also it is generally known thatsuch locks depend for the operation uponthe alignment of a plurality of elements in a preselected manner which Vpermits the operation of a bolt. These elements are usually in the form of discs, commonly Vcalled tumblers, each of which is provided with a notch or recess, called a gate, the alignment of the gate determining when the bolt can be moved. It is common for these locks to be provided with three discs, although more could be used. The security of such locks is dependent upon the fact that the number of orders or permutations of the possible relative positions of each disc before all of the gates come into register, which gives the correct combination, is s o large that the chances of these notches or gates being aligned by a person not familiar with the combination is so small as to be negligible.

The tumblers are operated through means of a member 'commonly referred to as a drive wheel or driving cam which also has a special gate. An element called a fence mounted on a pivoted fence-lever extends transversely across the edges of all of the tumblers and is adapted to drop into the gates when all of the gates in the tumblers are in alignment and when the drive wheel is manipulated vto permit the fence-lever to drop. Conventionally,

Ythe fence is held in such a position that it is slightly spaced from the outer peripheries of all of the tumblers. However, because of the diiculty in manufacture, it is almostimpossible to manufacture all of the parts, in-

cluding the tumblers, to such close tolerances that there will `be the same slight difference in the space between the outer edges of the different tumblers and the fence. Accordingly, by a very careful manipulation of the drive jwheel to a position such that the fence drops against the edge of the highest tumbler, a skilled person can detect by feel or by a very minute sound or click when one of the gates is aligned with the fence. Then by continuing to manipulate the drive wheel by means of the dial, the gate of the next highest tumbler can be aligned with the fence and, therefore, with the gate of the iirst tumbler,

and so on until the correct combination is found and the i 'security of the lock is broken. Accordingly, heretofore, because of the defects generally mentioned above, the security of a so-called combination lock against a skilled person has been limited.

In accordance with the present invention, means are provided for preventing the fence-lever from contacting the drive wheel and seating in the special gate therein` Furthermore, the fence-lever can be dropped into contact with the drive wheel and enter the special gate only when this drive wheel gate is substantially aligned with the fence. This avoids a defect of prior devices' in that the ice drive wheel cannot be turned suiiiciently to'manipulate-the tumblers when the drive Wheel is in contact with the fence-lever.

Also, in order to insure that the tumblers cannot be vibrated or walked by `oscillating the drive Wheel over its limited arc of movement, interlocking means are provided in the form of serrations on the'fence and on the peripheries of the tumblers so that as soon as the fence-lever 1s permitted to seat in the drive wheel gate, the fence rests on the tumblers withv their serrated surfaces inter-engaged, rendering manipulation of the tumblers practically impossible.

The primary object of the present invention is to provide a combination lock in which a manipulation of the dial will not give any indication of the position of the gates in any of the tumblers. y'

Another object is to provide a combination lock with' a drive wheel having means for selectively preventing the fence-lever from seating in the drive Wheel gate and for permitting rotation of the drive wheel only when the fence is held away from the peripheries of the tumblers.

Another object is to provide a combination lock in which the drive wheel cannot be rotated to manipulate the tumblers when the fence lever is in position to contact vthe drive wheel. y

Another object of the present invention is the'provision of a combination lock having interlock means maintaining the fence out of contact with the tumblers at all times except when the fence is substantially aligned with the drive wheel gate.

Another object is* to provide a combination lock in which the drive wheel cannot be rotated to manipulate the tumblers when the fence lever is in position .to engage the drive wheel and having interlocking vmeans between ,the tumblers and the fence to prevent the walking of the tumblers when the fence lever is positioned to `engage the drive wheel.

A still further object is to provide an improved combination lock in which the fence can be held in spaced relation to the outer edges of all of the tumblers until the gates in all of the tumblers are brought into alignment.

Another object of the present invention is the provision of a novel combination lock which is normally biased to a condition maintaining the fence-lever out of contact with the drive wheel gate, and which can be actuated to engage these elements only when the drive wheel gate and tumbler gates are substantially aligned with the fence.

Other objects, advantages, and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein several preferred embodiments of the invention are shown.

In the drawings:

Figure 1 is a horizontal section of a combination lock constructed in accordance with one preferred embodiment of the present invention, taken along the lines 1-1 of Figure 2;

Figure 2 is a rear elevation of the combination lock illustrated in Figure l, with parts of the lock housing broken away to illustrate the internal arrangement thereof;

Figure 3 is a vertical section of the embodiment illustrated in Figure l, taken along the lines 3 3 of FgureZ;

Figure 3a is a vertical section of the embodiment illustrated in Figure l, showing the lock in condition with the fence seated in the tumbler gates, taken along the lines 3 3 of Figure 2;

Figure 4 is a rear elevation of a combination lock constructed in accordance with a second embodiment, with parts of the lock housing broken away;

e Figure 5 is a vertical section of the modification illustrated' in Figure "4," conditionedwith the fence out p f modified form of combination lock, with part of the lock housing cover plate broken away;

Figure 7 is avertical section of the modification illustrated in Figure 6, showing the lock conditioned to maintainthe fence out of contact with the tumblers, taken along the lines 7--7 of Figure 6;

Figure 7a is a vertical section of the modification illusl` trated in' Figure 6, showing the lock conditioned with the fence seated in the tumbler gates, taken along the line 7-7 of Figure 6;

Figure 8 is a horizontal sectionof a combination lock l embodying still a further modification; j

Figure 9 is a vertical longitudinal section illustrating the sliding bolt and associated components of the modification shown in Figure 8, taken along the lines 9-9 of Figure 8; and l Figure 9a is a vertical longitudinal section of the modification illustrated in Figure S, showing the lock conditioned with the fence seated in the tumbler gates, and taken along the lines 9-9 of Figure 8.

Referring to the drawings, wherein like reference characters designate corresponding parts throughout the several figures, and particularly toFigures I to 3a inclusive, the illustrative drawings show a conventional combination lock modified in such a manner as to permit the application of an embodiment of the present invention. The conventional lock comprises a casing 11 connected by a press fit to a hollow sleeve 12 which projects through a door 13. In the casing, a plurality of tumblers 16, 17 and 18 are rotatably mounted on a cylindrical boss 11a integral with the casing 11, the boss being substantially coextensive with the sleeve 12. Secured to the outer end of the sleeve 12 is a suitable escutcheon plate 19. The casing 11 is secured to the door 13 bythe sleeve 12 and suitable screws or like fastening means.

Inside the sleeve 12 is a shaft 21, the inner end of which has rotatably fixed thereto a drive wheel or driving cam 22. The opposite end of the shaft 21 has a dial 23 fixed thereto. As will be more clearly explained hereinafter, the dial 23 and its hub 23a constitute the means `through which the tumblers 16, 17, and 18 of the combination lock are manipulated.

Each of the tumblers 16. 17, and 18 is of conventional construction and is divided into two parts, an inner part serving as a hub and an outer part having a suitable notch or gate 16a, 17a, and 18a, respectively, it being understood that all of the gates lof the tumblers must bein proper alignment in order to operate the bolt of the lock. Conventional means are provided for changing the relative position between the hub portion and the outer portion of the tumblers in order to change the lock combination. Suitable fixed washers having small detents which engage accommodating recesses in the integral boss 11a of the housing 11 are placed between the hubs of adjacent tumblers so that from the standpoint of mechanical friction each of the tumblers is completely isolated from the other. One of such Washers is indicated at 26.

Between one side of the washer and the next adjacent tumbler is a flyer 27 having an outwardly projecting detent 27a. The annular portion of the flyer 27 serves as a spacer while the outwardly projecting detent 27a serves as an element through which one of the tumblers is driven by a laterally projecting detent on the next adjacent tumbler. This construction just described in general is conventional and therefore further details are considered unnecessary.

The drive wheel 22 is screw-threadeclly secured to the shaft 21 and a suitable key 31 is provided to lock the drive wheel in nonrotatable position on the shaft 21. The drive wheel 22 is provided with a lateral projection 32 which is adapted to engage the outwardly extending detent on the flyer 27 between it and the tumbler 18. It will be readily understood that when the dial 23 is rotated to rotate the drive wheel 22, the projection 32 will drive the tumbler 18 and through the intermediate yer 27 between the tumblerlS and the tumbler 17 the latter will be driven, and so on, including the tumbler 16. It will also be well understood that the gates 16a, 17a, and 18a of therespective tumblersmay be brought into registry with each other in the well-known manner when the proper combination is obtained by turning the knob 23a first to the right, lining up the gate in one tumber, then to the left, lining up the gate in the second tumbler, and then to the right again, lining up the third tumbler, and so on, ifthe lock is provided with more than three tumblers.

The lock is provided with a bolt 33 which is adapted to slide in a suitable guide formed in the casing 11, the bolt 33 being operated by a fence-lever 34 pivotally attached thereto by a screw '36. A suitable spring 40 is provided for the purpose of urging the fence-lever 34 towardl the tumbler. The fence-lever 34 is provided with a laterally projecting arm 37, commonly referred to as a'fence, which is adapted to engage the gates 16a, 17a, and 18a when the tumblers are in proper relative position. The drive wheel gate 22a is complemental to the shape of a depending boss or dog 38 on fence-lever 34. The lowest point of the boss 38 normally rides on the outer periphery of the drive wheel 22. The periphery of the drive wheel 22 andthe size of the boss 38 are such that 4the fence 37 is slightly spaced from the outer periphery of all of the tumblers.

As is usual, the lock is provided with a suitable device to prevent tampering, so that in the event an attemptvis made to drive the shaft 21 inwardly toward the casing, the bolt 33 would be locked in position. To this end, a suitable elementr41 having an end portion 41a which engages the outer face of the outer tumbler 18 is provided. The element 41 is pivoted on screw 43 and is provided with a curvedend 41b which partially encircles a llocking pin 44 when the parts of the lock are in normal position.' The locking pin 44 is adapted to slide in a suitable guiding recess in the casing 11 and is provided with a C-shaped washer 46 which engages a groove'in the pin 44. One side of the washer 46 engages the curved end portion 41h of the element 41 and a suitable spring 47 is provided for normally urging the pin 44 in upward position where it could engage a notch in the under side of the bolt 33. It will be readily apparent thatin the event the end 41a of the element 41 is moved, as when an unauthorized person attempts to disturb the parts of the lock, the element 41 would pivot around the screw 43 and its`opposite end 41b would become disengaged from the washer 46, thereby permitting thespring47 to urge the locking pin 44 into such a position as to engage the recess in .the under side of the bolt 33 to prevent movement of the latter. f

The construction described, so far is conventional. The present invention resides in inclusion of a protective interlock arrangement by modification of the association between the drive wheel 22 andthe fencelever 34, together with provision of -retraotable stop means in the combination lockwhich prevent the depending boss 38 from vseating in the special gate 22a in the drive wheel at all times except when the drive wheel gate 22a and the tumbler gates 16a, 17a, and 184 are properly aligned with the fence 37, so that a person unfamiliar withr the combination cannot manipulate the dial 23 in any manner to give him a clue to the combination of the lock. In the embodiments hereinafter described, the' retractable stop means take different specitic.forms,-eaclr of WhGll has the common function of maintaining the fence-lever and fence out of contact with the drive wheel and tumblers until -a preselected combination condition is set up.

In the embodiment illustrated in Figures 1-3a the stop means takes the form of a gate shield 50 constructed of a suitable resilient metallic material and secured to the rear cover plate 11b` of the lock housing 11 by screws 51 or other suitable securing means. The shield 50 extends in a generally horizontal direction from a corner of the lock housing to a point generally overlying the axis of the drive wheel 22, and is provided with a curved inwardly projecting shoulder 52 normally underlying' the lower end of the projecting boss 38 on the fence-lever 34. The shield 50 is normally disposed underlying the -boss 38 to maintain the fence-lever 34 in a suitably elevated position with the fence 37 out of contact with the peripheries of the tumblers 16, 1-"I and 18.

The shield 50 is preferably constructed in the form of a leaf spring which resists deforming forces in the plane of the leaf spring but readily yields to such forces directed along axes generally perpendicular to the plane of the leaf spring. As will be seen in Figure 3,v the fence-lever 34 is a relatively thick element compared to the drive wheel 22, and the drive wheel 22 -is normally disposed inwardly of the outer end of the fence-lever boss 38 and curved portion 52 of the shield 50 by means of a helical coil spring 53 surrounding the central shaft 21 adjacent its coupling with the dial 23. The coil spring 53 extends into and abuts against a wall portion of an annular recess 23b disposed within the hub 23a ofthe dial 23. The dial 23 is tted within a cylindrical recess 19a in the escutcheon plate 19 and is normally spaced from the rear wall of the cylindrical recess 19a by means of the coil spring 53, thus maintaining the drive wheel 22 retracted out of contact with the shield 50. Likewise, a T-shaped stud 55 is formed in the rear face of the drive wheel 22 and projects rearwardly therefrom, to cooperate with an arcuate slot 56 'formed in the cover plate 11b of the housing 11 in registry with a portion of the path of rotation of the T-shaped locking stud 55. The arcuate slot 56 at one end thereof is enlarged as at 56a for the entrance of the T-shaped stud 55 therethrough, the remaining portion of the arcuate slot being of a size to merely accommodate the narrow shank of the T-shaped stud. The enlarged portion 56a of the slot 56 is located relative to the orientation of the gate 22a in the drive wheel 22 to permit entry of the T-shape'd lstud 55 therethrough immediately preceding the point where Ithe drive wheel gate 22a is positioned to receive the depending boss 38.

The spacing of the lower face of the fence 37 above the periphery of the tumblers 16, 17 and 18 when the fence-lever 34 is held in its elevated position by the shield 50, relative to the spacing of the lower end of the boss 38 above the periphery of the drive wheel 22, is such that when the shield 50 is exed out of position to Support the fence lever 34 in elevated position, the lower` tip of the boss 38 would be suspended out of contact with the drive wheel periphery if the lower face of the fence 37 contacts the periphery of any of the tumblers 1'6, 17 and 18. In a preferred embodiment, the fence 37 is maintained approximately 3%000 of an inch above the periphery of the tumblers 16, 17 and 18, and the lower tip of lthe boss 38 is spaced approximately %000 of an inch from the outer diameter of the drive wheel 22 when the fence lever 34 is supported by the shield 50. Thus, when one of the tumbler gates is out of alignment with the fence 37 when the shield is biased out of supporting position, the lower tip of the boss 38 remains spaced approximately 2%000 of an inch from the drive wheel periphery when the fence rests on the non-registering tumbler.

By means of this construction, the dial 23 and shaft 21 are normally. biasedA outwardly :toward `the open .end'clf the cylindrical recess 19a 'in the escutcheon plate 19 for manipulation of the dial in setting up a desired combination. With the shaft 21 biased in this position by the coil spring 53, the driving projection 32 of the drive wheel 22 is disposed to engage the detent 27a on the flyer 27 associated withvthe tumblerl 18 to drive the tumbler. The tumblers 16, 17 and 18 may be rotated through rotation of the drive wheel 22 in this position 'to align the gates 16a, 17a, and 18a in the tumblers with the fence 37. This, in accordance with conventional practice, is effected by rotating the knob 23a of the dial 23 first in a clockwise direction to align a selected number with an index on the escutcheon plate 19, then in a counterclockwise direction a preselected number of turns toa selected number, and again in a clockwise direction to a third number of the combination.

After the combination is setup in this mannenthe dial 23 is rotated again counterclockwise to align a preselected number on the dial 23 with an index on the escutcheon plate 19, at which point the T-shaped stud 55 is registered with the enlarged portion 56a of the arcuate slot 56. The dial 23 is then forced inwardly against the bias of the coil spring 53, which projects the T-shaped stud 55 through theenlarged opening 56a of the arcuate slot 56, and the dial 23 is rotated to shift the T-shaped stud v55 throughthe` length ofthe arcuate slot 56 to the bottom thereof as'viewed in Figure 2. The axial movement of the shaft 21 and the drive wheel 22 coupled thereto to project the stud 55 through the enlarged portion of thearcuate slot 56 brings a peripheral portion of the drive wheel 22 into engagement with the inwardly projecting portion' 52 of the shield 50 and moves or pushes its curved portion 52 rearwardly against its resili-Y ent bias out of engagement with the lower end of the boss` 38 onthe fence-lever 34. If the gates 16a, 17a and 18a of the tumblers are in alignment with the fence 37 to permit the fence to seat therein, the boss 38 will 'fthen -rest against the periphery of the drive wheel 22, and rotation of the drive wheel 22 Within the limits determined by the arcuate slot 56 permits the fence-lever boss 38 to drop into the peripheral gate 22a of the drive wheel to withdraw the fence-lever toward the left-hand end of the lock housing 11 as viewed in Figure 2, retracting the bolt 33 from locking position.

As will be seen in Figure 2, the outer peripheries of the tumblers are provided with continuous serrations 60 which are adapted to be engaged by a series of complemental serrations 61 on the under side of the fence 37. This is in order yto assure that the tumblers cannot be walked around byoscillating the drive wheel 22 through the limited arc permitted by the slot 56. When the shaft 21 and drive wheel 22 are projected inwardly of the casing to project the T-shaped stud 55 through the arcuate slot 56, the serrations 61 on the under side of the fence 37 will interlock with the complemental serrations 60 on the peripheries of those tumblers whose gates are out of proper alignment with the fence 37, preventing the fence-lever boss 38 from contacting the periphery yof the drive wheel 22. It will be seen from this that no manipulation of the drive wheel 22 will make it possible to walk the tumblers in an attempt to open the lock. The engagement between the serrations on the -fence 37 and peripheries of the tumblers will insure that -the tumblers cannot be rotated by any other means.

A modification of this protective interlock arrangement is 'illustrated in Figures 4, 5 and 5a, wherein components of a combination lock arranged in accordance with this embodiment, corresponding to combination lock parts described in connection with the first embodiment, are indicated by the same reference characters. In this embodiment, the fence-lever 34 corresponding substantially to the fence-lever illustrated in the first embodiment but is provided with an integral arcuate leg 34a inclined downwardly from `a point near the pivot screw 36 toward the lower periphery of the drive vwheeltZZ.A

v7 The retractable stop means in this embodiment takes the form ofv vertically disposed leaf spring 6S depending from a point adjacent the top of the housing 11, to which it is aiixed by means of suitable screws or the like 66, beyond the horizontal axis intercepting the shaft 21. The leaf spring stop 65 is provided with an inwardly bowed portion 65' overlying a portion of the periphery of the drive wheel 22 and is formed with a lip 67 at the lowerend thereof normally underlying and supporting the downwardly projecting leg 34a of the fence-lever 34 to maintain the fence-lever boss 38 and fence 37 elevated out of contact with the drive wheel 22 and -tumblers respectively. 1

`It will be seen that on setting up the combination through rotation of the tumblers 16, 17 and 18 to align their gates with the fence 37, and shifting the drive wheel 22 inwardly to project the T-shaped stud 55 through the enlarged portion 56a of the arcuate slot 56, a portion of the drive wheel 22 underlying the bowed portion 65 of the leaf spring stop 65 will engage the leaf spring and force the lower end thereof rearwardly towards the cover plate 11b 'of the lock housing, withdrawing the lip 67 from underneath the fence-lever leg 34a and permitting the fence-lever to rotate downwardly under bias of the spring 40 to bring the boss 38 into contact with the drive `wheel and enter the fence 37 in the aligned tumbler gates. Further rotation of the drive wheel 22 within the limits permitted by the arcuate slot 56 will seat;the fencelever boss 38 in the special gate 22a of the drive wheel 22 to retract the bolt 33 into the lock housing 11.

The relative spacing of the boss 38 and fence 37 over the drive wheel and-tumbler peripheries is generally that employed in the first-described embodiment, so that the boss 38 will be prevented from contacting the drive wheel outer diameter if any of the tumblers are improperly laligned -and the fence accordingly contacts one of the tumbler peripheries. l

A third embodiment representing another modification of the protective interlock arrangement is illustrated in Figs. 6, 7, and 7a, wherein the combination lock components arranged in accordance with this embodiment and corresponding to components described in connection with the rst embodiment are again indicated by the same reference characters employed in that description. In this embodiment the drive wheel 22 keyed to the end of the manipulating shaft 21 is slightly modified to provide a peripheral gate designated 22a' occurring in the form of a recess disposed in the periphery of the drive wheel and extending onlyfrom a point approximately midway of the outer and inner faces of the drive wheel 22 through the inner face thereof.

The rearcover plate 11b of lock housing 11 is provided with an arcuate boss '70 coinciding with a portion of the path of a stud 71 projecting from the outer face of the drive .wheel 22. The arcuate boss 70 is cut away between the limits identified by the reference characters 70 through approximately 90 of arc to permit the resiliently biased shaft 21 and drive wheel 22 to be projected rearwardly with the stud 71 positioned within the cut-away portion of the boss 70. It will be seen, therefore, that the stud 71 and boss 70 in elect perform the equivalent functions of the T-shaped stud 55 and the arcuate slot 56 of the first two embodiments.

The uppermost one-of the limits '70 defining the cutawayportion of the boss 70 isso located to permit the shaft 21 and drive wheel 22 to be projected rearwardly towardthe cover plate 11 immediately preceding the point where the drive wheel gate 22a' is positioned to receive the depending boss 38 of the fence-lever 34. This position is identified with alignment of a preselected number on the dial 23 with an index mark on the escutcheon plate 19. Further rotation of the dial 23 to move the stud 71 through the cut-away portion of the boss 70 effects lregistry of the fence-lever boss with the drive Wheel gate 22a'.

i The retractable stop means in this embodiment is in the form of a bell crank stop 72 pivoted between the bifurcated arms 73 disposed on the inner face of the cover plate 11b by means of a pivot pin 73. A stop coil spring 74 is wound around the pivot pin 73' with one end extending under the bifurcated arms 73 and the other end against the uppermost arm of the bell crank 72 to bias the same upwardly toward the top of the lock housing 11. The upper arm of the bell crank 72 underlies a portion of the shank of the fence lever 34 between the boss 38 and the pivot screw 36 to maintain the fence 37 and boss 38 out of contact with the tumbler and drive wheel peripheries, respectively. In this position, the lower arm of the bell crank lever 72 rests against the rear face of the drive wheel 22 adjacent the periphery thereof in a position to be cammed rearwardly by the drive wheel 22 on projection of the drive wheel stud 71 into the cut? away portion of the boss 70.

With the fence lever 34 in elevated position as illustrated in Fig. 7, it will be noted that the boss 38 over-y lies the uninterrupted outer portion of the periphery of the drive wheel 22, so that accidental lowering of the boss 38 into contact with the drive wheel would not permit registry with the drive wheel gate 22a'. The portion of the arm of the fence-lever 34. between the boss 38 and pivot screw 36 in contact with the upper arm of the bell crank 72 is chamfered or beveled as indicated at 34b to permit the fence lever to be lowered sufficiently on rocking of the bell crank 7 2 downwardly under inwardly projected movement of the shaft 21 to permit seating of the boss 38 in the drive wheel gate 22a.

On manipulation of the dial 23 to bring the tumbler gates 16a, 17a and 18a into registry with the fence 37 and project the shaft 21 inwardly kafter the dial is aligned with the proper index mark to insert the stud I1 into the cut-away portion of the arcuate boss 70, the rearward movement of the drive wheel 22 cams the lower arm of the bell crank 72 downwardly and rearwardly towards the cover plate 11b, lowering the bell crank arm upon which the fence-lever 34 rests to permit the fence 37v to enter the aligned tumbler gates and dispose the fence' lever boss 38 against the periphery of the drive wheel 22. Further rotation of the drive wheel 22 to shift the drive wheel stud 71 through the cut-away portion of the arcuate boss k70, seats the fence-lever boss 38 in the drive wheel gate 22a and shifts the fence-lever toward the lefthand end of the lock housing as viewed in Fig. 6, re-v tracting the bolt from the bolt keeper. i

VAlso in the embodiment, the boss 38 and fence 37 are yspaced above the drive wheel and tumbler peripheries in the same general relation as that employed in the previously described embodiments to prevent the boss 38 from contacting the drive wheel periphery if any of the tumblers are improperly aligned so that the fence comes to rest upon one of the tumbler peripheries, f

A further embodiment is illustrated in Figs.. 8, 9 and 9a wherein the components arranged in accordance with this embodiment and corresponding to parts described in connection with the previous embodiments are indicated by the same reference characters. The pivotal coupling of the fence-lever 34 to the sliding bolt is dispensed with and a sliding bolt 75 projecting from the lock housing 11 is provided having an integral plate 76 extending into the housing and around the shaft 21. The Ashaft 21 is provided with a bearing sleeve 77 having an annular recess to accommodate a suitable slot 76' in the inwardly projecting bolt plate 76. The sleeve 77 therefore serves asa guide for the bolt 76 in cooperation with a guide screw 78 having a head overlying and contacting a beveled portion 76" along the lower surface of the plate 76 to confine the bolt to rectilinear movement.

A fence-lever 79 is pivotally mounted by means of a pivot screw 79' to the inner wall of the lock housing 11 and provided with a fence arm 80 projecting toward 'the shaft 2l and extending through substantially. the

depth of the lock housing. The outer surface of the arm 80 adjacent the tumblers 16, 17 and 18 forms the fence cooperating with the tumblers. The pivot fence lever 79 is likewise provided with an upwardly extending arm 81 forming an operating arm therefor normally in abutment with a suitable resiliently biased pin 82 projecting slightly from an inwardly disposed face of the bolt 75 to bias the fence-lever 79 in a counterclockwise direction as viewed in Fig. 9. An outstruck lug or shoulder 83 is provided in the bolt plate 76 disposed to be engaged by the operating arm 81 of the fence lever 79 on counterclockwise rotation to retract the bolt 75 from locking position. This lock is provided with a drive wheel S disposed forewardly of the tumblers 16, 17 and 18 in the direction of foreward wall of the lock housing 11 and is provided with a suitable driving stud 85 adapted to engage the projecting detent 27a of conventional iiyer 27 associated with tumbler 16, the drive wheel 85 positioning the tumblers in reverse order compared to that effected in the previously described embodiment.

In this embodiment, the drive wheel 85, shaft 21 and dial 23 are normally biased in rearwardly projected position with the drive wheel adjacent the tumblery 16 by means of a suitable coil spring 86 surrounding the shaft -2,1 and extending into a suitable annular recess formed in the sleeve 77, the opposite end of the coil spring 86 being disposed against the adjacent face of the drive wheel 85. The drive wheel 85 is provided with a special gate 85a of conventional form adapted to accommodate a projecting lip 80' on the fence arm 80. Clockwise rotation of the drive wheel 85 from position indicated in Fig. 9 will progressively effect seating of the lip 80' in the drive wheel gate 85a and rotates the fence lever 79 counterclockwise to cam the bolt 75 inwardly of the lock housing 11 through interaction of the operating arm 81 and lug 83. Entrance of the lip 80' into the drive wheel gate 85a can only be effected, of course, when the gates of the tumblers 16, 17 and 18 are likewise in alignment with the drive wheel gate.

A fixed L-shaped stud 87 corresponding in function substantially to the stud 55 in the first described embodiment, projects rearwardly from the front wallV of the housing 11 through the opening 76 of the bolt plate 76 and terminates adjacent the front face of the drive wheel 85. The drive wheel 85 is provided `with a suitable arcuate slot 88 in registry with the fixed stud 87 throughout a preselected arc of rotation of the drive wheel 85 and an enlarged portion 88 is formed at'one end of theslot to accommodate the head of the L-shaped stud 87 for entrance of the stud 87 through the slot 88. The stud 87 prevents movement of the drive wheel 85v and shaft 21 outwardly of the lock except when the enlarged portion 88 of the slot 8S is in registry with the head of the stud 87. In this position, the shaft 21 and drive wheel 85 can be withdrawn towards the front of the housing against the bias of the spring 86 and rotated through `the limit of the arc defined by the slot 88. Only in this withdrawn position of the` drive wheel 85 isl the projecting fence portion 80' disposed to contact the periphery of the drive wheel 85 andseat in the gatey 85a thereof.

The protective interlocking means of this embodiment comprises a cylindrical operating element 90 threaded to the shaft 21 and extending to the rear cover plate 91 of the housing 11 and through a bore formed in a tubular boss 91 formed thereon.y The tubular boss 91' in this embodiment is the supporting element about which the tumblers are journaled. The cylindrical operating element 90 is provided with a beveled or tapered end 90' disposed at the rearwardly disposed end thereof. The cover plate 91 of the housing 1 1 is provided with a pair of guide lugs 92 having radially aligned bores therein through which a sliding pin 93 is extended and arranged for radial movement. A suitable coil spring 94 extends around the sliding pin 93 between the guide lugs-92 and biases the pin 93 on a radial-axisinwardlytoward-the .10 v cylindrical operating element 90. The outer end'` "f the sliding pin 93 projects outwardly of the outer lug 92 and is disposed in contact with a lateral projection integrally formed on the fence arm 80.

With the shaft 21V normally projected rearwardly within the lock housing '11, the inner end of the sliding pin 93 normally bears on the cylindrical yperiphery of the operating element 90 maintaining the pin 92 in the outwardly projected position illustrated in Fig. 8 against -the bias of the spring 94. In this position the pin 93 bearing against the lateral projection 80" of the fence-lever 79 maintains the fence arm 80out of vcontact with the peripheries of the tumblers 16, 17 and 18 4and drive wheel 85. However, when the tumbler gates 16a, 17a and 18a have been aligned through proper clockwise and countreclockwise rotation of the dial 23, and the shaft 21 and drive wheel 85 are shifted outwardly of the housing to project the stud 87 through the enlarged portion of the slot 88, the tapered or beveled end portion 90' of the operating element 90 is brought into registry with the inner end of the sliding pin 93. Such movement of the operating element 90 permits the pin 93 to be shifted radially inwardly toward-the axis of the shaft 21 under the resilient bias of the spring 94, withdrawing the outer end of the pin 93 from contactV with the projection 80 onthe fence arm 80 and permitting the fence to be rotated into the gates of the tumblers 16, 17 and 18 and lip 80 thereof to be seated in the drive Wheel gate a under the counterclockwise bias on the fencelever 79. Projection of the shaft 21 and drive wheel 85 inwardly again earns the pin 93r radially outwardly through interaction with the tapered portion of the operating element 90, rotating the fence-lever 79 out of contact with the tumbler peripheries. i

From the foregoing kdescription it will be seen that the present invention provides an improvement in combina- 'tion locks which clearly adds to the security thereof and which is relatively inexpensive to manufacture. Although the invention has been described in considerable detail, it will be. apparent to those skilled in the art that many variations are possible without departing from the inventive concept. Therefore, While l have particularly shown and described four specific embodiments of the invention, it is distinctly understood that the invention is not limited thereto, but that various modifications may be made without departing from the spirit and scope thereof, and it is desired therefore, that only such limitations shall be placed thereon as are imposed by the appended claims. What is claimed is:

l. ln `a combination lock of the kind having peripheral ly recessed tumblers, a spindle journalled'centrally of said tumblers, a driving cam iixed on said spindle and disposed rearwardly of said tumblers, a bolt, a lever for operatingsaid bolt, said lever having fence means thereon overlying said tumbler peripheries and adog to overlie and selectively engage the periphery of said driving cam, said driving cam having a peripheral gate to accommodate said dog of said lever and permit said fence means to seat in said tumbler recesses for Ymoving said bolt, means supporting said driving cam and spindle for axial movement between aforward and a rearward position of axial adjustment relative to said tumblers, said driving cam having means for adjusting said tumblers in response to rotation of said driving cam when said driving cam occupies said forward position, lever supporting means supported independently of said driving camv at a fixed station and extending in the pathof movement of said driving cam for normally supporting said lever in a position spacing said dog and fence means out of engagement with said driving cam and tumblers when said driving cam occupies said forward position and movable by said driving cam to a position releasing said lever from such supported condition during axial shifting of said spindle and driving cam between said lforward and rearward positions-to permit operative engagement ofsaid dog-With the driving cam periphery when said driving cam occupies said rearward position; the improvement of-which comprises a rearwardly projecting member lon said driving cam, an apertured member disposed at a xed station and spaced rearwardly of said driving cam and said lever supporting means, having an aperture in alignment with said projecting member when said driving cam is in a preselected position of orientation wherein said driving cam gate is out of alignment with said dog for accommodating said projecting'member during axial movement of said driving cam between said forward and rearward positions, and aperture-bounding surfaces positioned to be in restraining engagement with said projecting member only at all times when said driving cam is in nonregistry with either of said forward and rearward positions for holding said driving cam against rotation, lsaid aperture-bounding surfaces terminating short of the position of said projecting member corresponding to the rearward position of said driving cam whereby said driving cam is free for rotation at said forward position to adjust said tumblers and is free for rotation at said rearward position to move the released lever and said bolt.

j. 2. In a combination lock of the kind having a lock housing, peripherally recessed tumblers, a rotatable driving cam, means supporting said driving cam for axial movement between innermost and outermost positions of axial adjustment, said driving cam having means for adjusting said tumblers when said driving cam is positioned in said innermost position, means resiliently biasing said driving cam to said innermost position, a bolt, a lever for operating said bolt, said lever having fence means thereon overlying saidv tumbler peripheries and a nose portion to selectively engage the periphery of said driving cam, said driving cam having gate means to accommodate said nose portion and permit said lfence means to seat in said tumbler recesses for moving said bolt in response to rotation of said driving cam when said driving cam occupies said outermost position, and shielding means mounted on said housing normally Isupporting said lever to space said nose portion and fence means out of engagement with said driving cam periphery and tumblers during adjustment of said tumblers when said driving cam is disposed at said innermost position, said shielding means being positioned to be successively engaged and moved outof supporting relation with said lever by said driving cam during axial `shifting of said driving cam between said innermost and outermost positions of axial adjustment to free said nose portion to operatively engage said driving cam'gate when said driving cam occupies said outermost position; the improvement of which comprises a rearwardly projecting stud on said driving cam having an enlarged head thereon, means decoupling said driving cam from said tumblers upon axial shifting of said driving cam from said innermost position, said housing having an aperture therein extending entirely therethrough to receive ,said stud head upon outwardvaxial displacement of said driving cam from its innermost position at only one position of orientation of said driving cam wherein said driving cam gate means is out of alignment with said nose portion, the bounding walls of said aperture being disposed to engage said stud head to restrain rotation of said driving cam only at all axial positions of said driving cam between said innermost and outermost positions, said boundingl walls terminating short of the position of said stud head corresponding to the outermost position of said driving cam to free said stud head from restraining engagement with said bounding walls when said driving cam occupies said outermost position, said lock housing having arcuate slot means communicating with said aperture for accommodating said projecting stud throughout rotation of said driving cam through a preselected angle from said one position of orientation when said driving cam occupies said outermost position, and means on said housing bounding said arcuate slot means and bearing 1against said. stud head when said studis disposed in said arcuate slot-'forholding said driving cam against axial withdrawal from said outermost axial position.

3. In a combination lock having peripherally'recessed tumblers, a rota-table driving cam having'projecting means thereon, means supporting said driving cam for axial movement between irst and second spaced positions of axial adjustment, said driving cam having means for adjusting said tumblers upon rotation of said driving cam when said driving cam is positioned at said first position, a bolt, a lever for operating said bolt having fence means thereon overlying said tumbler peripheries and a nose portion for selectively engaging the periphery of said driving cam, said driving cam having a peripheral gate therein for accommodating said nose portion to move said lever and said bolt in response to rotation of said driving cam and to permit said fence means to seat in the tumbler recesses; means for preventing operative engagement of said lever nose portion with said driving cam gate to prevent movement of said bolt responsive to driving cam manipulation except when said driving cam occupies said second position comprising shielding means normally spacing said lever from said driving cam and tumblers and positioned to release said lever into engagement with the driving cam periphery during axial shifting of said driving cam from said first position to said second position, and abutment means disposed to be in restraining engagement with said projecting means on said driving cam only at all times while said driving cam is in nonregistry with said lirst and second positions for holding said driving cam against rotation from a preselected orientation wherein said driving cam gate is out of alignment with said lever nose portion, said abutment means terminating short of the position of said projecting means corresponding to the second position of said driving cam to free said driving cam for rotation at said first position to adjust said tumblers and at said second position to move the released lever and said bolt.

4. A combination lock comprising a housing, a plurality of disk-like tumblers interconnected by lost motion driving connections and being operably mounted within said housing, said tumblers each having a peripheral gatf ing therein, an elongated, manually rotatable dial shaft extending into said housing, a disk-like driving cam secured to said shaft within said housing for rotation with said shaft, alost motion driving connection between said driving cam and one of `said tumblers, means supporting said driving cam for axial displacement over a range of movement between a rst limit` position adjacent said tumblers` anda second limit position relatively remote from said tumblers, means biasing said driving cam toward 'said first limit position, said driving cam being rotatable at said yfirst limit position to adjust said tumblers, a bolt movably mounted on said housing, amovable fence leven secured to said bolt for operating the same and having a fence overlying said tumblers,`said fence lever having ,al cam follower nose for selectively engaging the periphery of said driving cam, biasing means associated with said fence lever for continuously urging said nose toward said driving cam periphery, said driving cam having a gate in the periphery thereof to accommo date said cam follower nose and permit said fence means toV seat in said tumbler gates for moving said bolt in response to rotation 'of said driving cam when said driving cam occupies said second limit position, a leaf spring stop mounted in; said housing in the path of axial movement of said driving cam and having alip portion engaging and supportingA said fence lever and biased to maintain said fence means out of engagement with said drivingv cam and tumbler peripheries, said stop means being tlexed bywsaid driving cam out of operative contact with said fence lever on axial movement of said driving cam from said first limit position to said second limit position to release said cam follower nose to engage in said driving cam periphery, a projecting stud on said driving cam extending in the ,direction of movement of said driving 13 cam from said iirst limit position and having an enlarged head thereon, means decoupling said driving cam from said tumblers upon axial shifting of said driving Icam from said first limit position, said housing having an aperture therein extending entirely therethrough to receive said stud head upon axial displacement of said driving cam from said first limit position when said driving cam is at one position of orientation wheren said driving cam gate is out of alignment with said nose, the bounding walls of said aperture being disposed to engage said stud head to restrain rotation of said driving cam only at al1 axial positions of said driving cam between said first and second limit positions, said bounding walls terminating short of the position of said stud head when said driving cam occupies said second limit position whereby said driving cam is free for rotation at said rst limit position to adjust said tumblers and at said second limit position to move the released lever and said bolt, said lock housing having arcuate slot means communicating with said aperture for accommodating said projecting stud throughout rotation of said driving cam through a preselected angle from said one position of orientation, and means on said housing bounding said arcuate slot and bearing against said stud head when said stud is disposed in said arcuate slot for holding said driving cam against withdrawal from ysaid second limit position when said driving cam is out of alignment with said one postion of orientation.

References Cited in the le of this patent UNITED STATES PATENTS 132,936 Sullivan Nov. 12, 1872 237,950 Bernhardt Feb. 22, 1881 821,548 Streeter et al: May 22, 1906 1,863,537 Aster .Tune 14, 1932 2,601,774 Behrens et al. July 1, 1952 2,775,113 Behrens Dec. 25, 1956 

